^I think it's because there's not much to say. We've all seen how good you are at recreations, I think people wanna see more of your creative side! (*cough*Inspiration Lake*cough* seriously, that was like one of the best parks on the site! let's see some more of it!!)
Sorry to hear you're dropping this. I've been crammed for time lately (school) so I haven't had as much time to check stuff out, analyze, and post solid feedback.
BUT since this is still open (and surprisingly I've got time to spare) I'll give some while it's here.
Archy - as usual, spot on. You really know how to nail the realistic style.
Landscaping/scenery - this is where your weaknesses lie. the canyon for the mine train seems a bit random and scrambled. It might just be because of the picture quality, I can't be sure. If there's any way you can variate the colors, that would significantly boost the realism. If you can't, the best thing you could probably do is to put some REAL dirt and rock in there (actual land, not scenery).
Also, it might be a little late now, but your water features (rivers and such) look a little....artificial. In order to have really nice looking ponds and streams, you need to use the mountain tool to make a trough of land, then raise the water so it's one square (or more) below land. If you have 8 cars, you can use the mountain tool even out of the SE.
Seriously, once you spiff up your landscaping, your parks will be spectacular.